Airbus is aiming to deliver the wing for the first flying A350-900 to the final assembly line in October, but is still assessing whether additional cautiousness over the manufacturing process will push back the maiden flight.
A350 programme chief Didier Evrard had stated in May that the airframer was making slower-than-expected progress on the wing drilling at its Broughton plant in the UK.
Experience with the highly-automated drilling - crucial to the production ramp-up - was taking time to accumulate and Airbus chief executive Fabrice Bregier said, during the Farnborough air show, that the airframer had resorted to manual drilling in places because it wanted to be "over-cautious" on the critical structure.
He points out that size of the 32m (105ft) composite panel means the company can ill-afford errors in drilling. "It takes a long time to make another," he says.
Bregier says the airframer has yet to determine whether this conservative approach will have an effect on the first flight schedule for MSN1.
"The most critical phase is now behind us," he says, although he adds that he would "never exclude" a "slight adaptation" of the programme - pointing out that Airbus is sticking rigorously to its aim of prioritising component maturity over the timetable.
He says that the airframer will complete a "virtual" first flight with the A350 by the end of this year, which will then give it "more confidence" on the maiden flight, which it has been planning to conduct in mid-2013.